This invention relates to the treatment of sericitic clays so as to produce an absorbent, adsorbent product having ion exchange capabilities or characteristics.
Two separate, different factors are especially important in connection with this invention. The first is the recognition of the fact that there is a continuing commercial demand or need for adsorbent and absorbent materials which are comparatively inexpensive in terms of what can be accomplished as a result of their use. Such materials are widely used for a variety of purposes such as, for example, in decoloring various different types of oils. The second of these factors relates to the recognition that what are now considered to be waste sericitic clay particles can be economically processed so as to provide an adsorbent and absorbent material capable of being utilized in fullfilling or satisfying this commercial need.
The sericitic clays referred to in this discussion are micaceous minerals normally containing a small amount of montmorillonitic-type material. The latter is not normally a true or traditional montmorillonite in that it does not have expansion characteristics on glycolation of montmorillonite. Clays of this type are mined in the San Joaquin Valley of California in the vicinity of various towns such as Taft, McKittrick and various others which are reasonably adjacent to the latter. A typical analysis of a sericitic clay of the type noted herein which is commonly utilized as cat litter, is as follows:
______________________________________ Silica 80.40% Aluminum Oxide 9.48% Iron Oxide 0.88% Calcium Oxide 0.20% Magnesium Oxide 0.54% Sodium & Potassium Oxides 0.15% Loss on ignition (largely combined water) 8.35% 100.00% ______________________________________
The composition of any such clay will normally vary throughout a deposit. Generally speaking, the deposit from which the sample upon which this analysis was obtained will not vary to such an extent as to gain either more or less than 10% more or less than any of the various ingredients specified except water. In this type of sericitic clay there will normally be cristobalite as an impurity within the sericitic material and a comparatively limited or minor amount of opaline quartz will normally be present. In general, approximately 40-60% by weight--normally about 50% by weight--of a quantity of this mineral will consist of amorphous silica which may be easily solubilized.
This silica will either be uncombined or will be combined so loosely with various other oxides that it can be extracted with the same methods as are applicable to the removal of purely uncombined silica or will be present in zeolitic type complexes. The alumina within a clay deposit of this sericitic type will also normally consist of both aluminum oxide which is uncombined or combined loosely with other oxides in compounds of such a character that it is capable of reacting as uncombined alumina or will be present within various complex zeolitic type compounds--normally silicates--which will usually contain various other ingredients such as magnesia, calcium oxide, iron oxide(s) and sodium or potassium oxide.
Comparatively large volumes of so-called "fines"--comparatively small particles--of sericitic clays are in effect by-products of the mining of such clays and the subsequent processing of such clays for use as cat litter and various other related applications. This processing primarily consists of sizing and placing the various particles of the clay in the appropriate bags or sacks or other containers. In the past, it has been uneconomic to do anything with these fines even though, at least in theory, they have been capable of being utilized in various.